Simon Hughes could be the man - one day - to tell Nick Clegg that the Coalition is no longer in the Liberal Democrats' interests

We learnt yesterday that Simon Hughes will stand for the deputy leadership of the Liberal Democrats.

A vacancy has arisen because of the decision of Vince Cable to step down in order, he explained, to focus on being Business Secretary.

Mr Hughes - seen as on the Left of his party - was a staunch defender of the Coalition deal after it had been sealed. He was hardly off the airwaves, appearing on TV's Question Time and Radio's Any Questions in the space of 24 hours - breaking the normal convention that no guest appears on both programmes in the same week.

That loyalty does not mean that Mr Hughes will stay true to the Coalition. He could become the champion of the party's Left if LibDems do disproportionately badly in future elections.

Bumpy times certainly lie ahead because of the looming public spending cuts. A new Labour leader's first task will be to fight the Liberal Democrats in next year's Scottish and Welsh elections. Labour will then turn its fire against the Liberal Democrats in major urban centres, particularly Liverpool, Sheffield and Newcastle. The Labour message will inevitably be 'The Liberal Democrats are keeping the nasty, cutting Tories in power'.

Tim Montgomerie